Instead of spell checking each sheet in your workbook one-at-a-time, you can spell check all of them at once and save yourself some time.
1. Right-click on a sheet tab at the bottom of your Excel spreadsheet.
2. Click Select All Sheets.
3. Go to the Ribbon.
4. Select the Review tab.
5. Select Spelling.
You can also skip steps 4-5 and simply press F7 on your keyboard.